#my-slider{
    position: relative;
    width: 790px;
}
.slider_list ul{
    list-style-type: none;
    position: relative;
    padding: 0;
    margin: 0;
}

.slider_list_item,
.slider_list_item_selected{
    position: relative;
    opacity: 0;
    transition: opacity 1s;
    text-align: center;
}
.slider_list_item_selected{
    position: 1;
    transition: opacity 1s;
}